Tablet pressing machines are known in various numbers from the prior art. Basically, generic tablet pressing machines have a rotor unit which is practically always carried by a driven spindle and which, together with the spindle, rotates about a vertically aligned rotation axis D. In addition, such a rotor unit comprises a matrix disc in which a plurality of matrices or matrix mountings are formed. The matrix mountings are provided to hold separately constructed matrices in them. Above and below the matrix disc, generally upper and lower die mountings are arranged, in which a plurality of upper and lower dies are arranged which are displaceable in the direction of the rotation axis D and engage by their ends into the matrices of the matrix disc. The upper and lower dies are actuated on a rotation of the rotor unit by cams which can be connected for example mechanically securely with a frame of the tablet pressing machine. However, the cams may also be constructed as discs which are rotatably mounted on the frame of the tablet pressing machine.
For the production of tablets, powdery material is supplied via a material supply to the matrices which are formed in the matrix disc, which material is then compacted by the upper and lower dies engaging into the matrices. With a sufficient compacting of the powdery material, a tablet is obtained which is then ejected from the matrix by a corresponding ejection movement of an upper or lower die and is guided out of the tablet pressing machines by suitable mechanical devices.
As the material which is to be tabletted can never be processed at 100% to tablets and, furthermore, contains in part highly effective medical components which, on inhalation, can be problematic, ranging up to being hazardous for an operator of the tablet pressing machine, a careful cleaning of the tablet pressing machine must be carried out when the material which is to be tabletted is changed, i.e. with a batch change. To do this, it is important in particular to bind powdery material which is present in the air and also on the rotor of the tablet pressing machine and in its environment, so that it can no longer be inhaled by the operating personnel. To do this, tablet pressing machines are known from the prior art which have a closed housing area in which at least the matrix disc of the rotor, but generally in addition also the upper and lower die mountings in addition to the associated dies and the actuating cams of the upper and lower dies are arranged. In order to bind the powdery material which is not processed into tablets, a spraying device for a cleaning fluid, such as water for example, is arranged in the closed housing of the tablet pressing machine. On a batch change, before the closed housing area is opened, a cleaning fluid is sprayed which washes out the suspended particles situated in the air and, in addition, as far as possible wets all the surfaces arranged in the region of the closed housing, to bind powdery material residues which are situated thereon. The powdery material residues which are bound in the cleaning fluid can then no longer get the air, but rather the closed housing area can now be opened and, for example, cleaned manually by the operating personnel.
Generally, an extensive dismantling of the tablet pressing machine is necessary for the cleaning method, which entails in part considerable down times, causing relevant costs. Any reduction in the down time during a batch change—for example by simplifying the cleaning method—therefore immediately brings financial advantages with it.
As already mentioned above, in a generic tablet pressing machine the material which is to be tabletted is directed to the matrices in the matrix disc via a material supply. Generally, such a material supply directs the powdery material on the upper side to the matrices formed in the matrix disc. To do this, a supply opening is formed in the material supply, which frequently overlaps several matrices of the matrix disc which are arranged one behind the other, and which material supply is often surrounded by a seal. This seal seals off the spacial area surrounded by the supply opening with respect to the environment. The seal is commonly guided at a minimal distance over the upper side of the matrix disc. Alternatively, sliding seals are also used. In both types of construction, however, a high-precision adjustment of the material supply and of the seal contained therein relative to the rotor unit is indispensable, in order to avoid excess wear on the matrix disc itself, on the seal or on the material supply. Also, the material abrasion which is inevitably entailed with the wear can be a problem when it is carried into the tablets which are produced on the tablet pressing machine. For this reason, the material supply in the constructions previously known from the prior art must be newly aligned accurately after the machine has been dismantled for example for cleaning purposes. This adjustment process here is frequently very complex and hence time-consuming. A dismantling of the material supply is, however, generally indispensable in the generic tablet pressing machines previously known from the prior art, because otherwise the powdery material residues situated in the region of the material supply, in particular the supply opening on the inside, and the contact region with the matrix disc, can not be detected during the cleaning method.